An ignition distributor base plate having integral resilient securing means

ABSTRACT

An ignition distributor including a hollow substantially cylindrical casing formed internally with a peripheral shoulder. A groove extends into the wall of the casing from the shoulder, and a contact breaker assembly base plate is seated on the shoulder. The base plate is formed with a slot which extends along a chord of the plate to define a resilient ear integral with the plate. A tapered screw, or other alternative expansion means is engaged in the slot, and urges the resilient ear in a direction away from the remainder of the base plate so as to urge the ear into the groove, and so clamp the base plate in position in the casing.

United States Patent n 1 Rees [ Mar. 27, 1973 [54] AN IGNITION DISTRIBUTOR BASE PLATE HAVING INTEGRAL RESILIENT SECURING MEANS [75] Inventor: Alfred Rees, Perry Barr, England [73] Assignee: Joseph Lucas (Industries) Limited,

Birmingham, England [22] Filed: July 22, 1971 [21] Appl. No.: 165,183

[30] Foreign Application Priority Data July 28, 1970 Great Britain ..36,4l5/7O [52] [1.5. CI. ..200/l68 R, 200/19 [51] Int. Cl. ..H01h 9/02 [58] Field of Search ..200/l90 C, 190 R, 31,168 R [56] References Cited UNITED STATES PATENTS 3,444,339 5/1969 Jukes ..20o 31x Primary Examiner-H. 0. Jones Attorney-Holman & Stern [5.7] ABSTRACT An ignition distributor including a hollow substantially cylindrical casing formed internally with a peripheral shoulder. A groove extends into the wall of the casing from the shoulder, and a contact breaker assembly base plate is seated on the shoulder. The base plate is formed with a slot which extends along a chord of the plate to define a resilient ear integralwith the plate. A tapered screw, or other alternative expansion means is engaged in the slot, and urges the resilient ear in a direction away from the remainder of the base plate so as to urge the ear into the groove, and so clamp the base plate in position in the casing.

10 Claims, 7 Drawing Figures PATENTEDHARZYIUB ,723,591

SHEET 1 OF 4 L 11 12 14 15 &

FIG. 1

INVENTOR A//rea 16665.

ATTORNEYS PATEWFDMARZHQB 3 723,591

SHEET 2 OF 4 Alfred Fees INVENTOR ATTORNEYS PATENTEUHARZ'IISYS ,723,591

SHEET 3 OF 4 FIG. 5.

INVENTOI? Alf/ed flees,

ATTORNEYS PATENIEUMmmn SHEET u [If 4 IGNITIGN DISTRIBUTOR BASE PLATE HAVING INTEGRAL RESILIENT SECURING MEANS This invention relates to ignition distributors for road vehicles.

An ignition distributor, according to the invention comprises a hollow, substantially cylindrical casing formed internally with a support surface and a groove extending radially into the casing from the support surface, a contact breaker assembly base plate engaged with said support surface, said base plate being formed with a slot extending from the periphery thereof along a chord of the base plate to define a resilient ear integral with said base plate, and clamping means for urging said resilient ear in a' direction away from the remainder of the base plate so as to urge said ear into said groove and thereby clamp the base plate in position in the casing.

Preferably, the base plate is provided with a pair of peripherally extending chamfered portions formed respectively on the part of the base plate defining said resilient ear and a portion of the base plate diametrically opposite said ear, said groove extending peripherally around the casing and being formed complementarily with said chamfered portions so that said clamping means urge said chamfered portions into engagement with said groove so as to clamp the plate against axial and lateral movement relative to the casmg.

Most preferably, one of said chamfered portions projects from the periphery of the plate.

Preferably, said clamping means comprises a tapered screw extending through said slot and engaged therein.

Desirably, said slot is provided with a part-circular portion intermediate the ends of the slot and said tapered screw is engaged in said part-circular portion.

In the accompanying drawings, which illustrate one example of the present invention,

FIG. 1 is a sectional view of the casing of an ignition distributor,

FIG. 2 is a sectional view to an enlarged scale of part of the casing of the distributor shown in FIG. 1,

FIG. 3 is a plan view of the base plate of the distributor,

FIG. 4 is a view similar to FIG. 3 of a modified base plate,

FIG. 5 is a plan view of an assembled ignition distributor utilizing the components of FIGS. 1 and 3, and

FIGS. 6 and 7 are plan views respectively of two further modifications of the base plate.

Referring to the drawings, the casing 11 of the distributor is cast in an aluminum alloy and includes a peripheral inwardly directed shoulder 12 extending at right angles to the inner surface of the casing. The casing 11 is also formed internally with a peripheral groove 13 extending radially into the casing 11 from the upper surface of the shoulder 12 and including an inclined surface 14 presented to the shoulder 12.

The casing 11 is arranged to house a contact breaker assembly (not shown) supported in conventional manner on a base plate 15 (FIG. 3). The base plate 15 is circular and is formed with a centrally disposed hole 16 through which in use, the cam shaft of the distributor extends. The diameter of the base plate 15 is substantially equal to the internal diameter of the casing l l and so the plate 15 can be inserted into the casing and will seat on the shoulder 12. Thus the shoulder 12 constitutes a support surface for the base plate 15. In order to retain the base plate 15 in the casing 11, the base plate 15 is provided with a pair of arcuate, peripherally extending chamfered portions 17,18 respectively and a slot 19 extending from the periphery of the plate adjacent the chamfered portion 17 along a chord of the plate. The chamfered portion 17 is defined within the periphery of the plate 15 whereas the portion 18, which is positioned substantially opposite the portion 17, projects from the periphery of the plate. Further the length of the slot 19 is arranged so that only a short portion of the base plate 15 extends between the closed end of the slot and the periphery of the base plate adjacent said closed end. In this way the slot 19 divides from the remainder of the base plate 15, a resilient ear 21 integral with the remainder of the base plate and having a chamfered outside surface defined by the portion 17.

In order to mount the base plate 15 in the casing 11 the plate is first tilted so that the chamfered portion 18 is presented to the casing. The plate 15 is then inserted into the casing until the chamfered portion 18, which extends from the periphery of the plate, is engaged in the groove, 13. The plate 15 is now allowed to drop into the casing whereby the plate seats on the support surface 12 and adopts the required horizontal position in the casing, the chamfered portion 18 remaining in engagement with the groove 13. A tapered self-tapping screw (not shown) is then engaged in the slot 19 and is screwed into the slot 19 so as to urge the resilient ear 21 away from the remainder of the base plate 15. Thus the tapered screw expands the plate and urges the chamfered portions 17, 18 into engagement with the groove 13 to clamp the base plate in position in the easing. Preferably the slot 19 is formed along its length with a part-circular portion 22, the tapered screw then being inserted into the part-circular portion 22. It is to be appreciated that the engagement of the chamfered portions 17, 18 in the groove 13 is sufficient to anchor the base plate 15 against both axial'and lateral movement relative to the casing 11 under the vibrational forces experienced by the distributor in use.

In a modification (not shown) the ear 21 of the plate 15 is initially bent towards the remainder of the plate 15 to reduce the distance between the portion 18 and theportion 11 of the plate. In this way, the plate can be dropped into the casing without the necessity of having to tilt the plate. It will be'appreciated that when the plate is dropped into the casing 11 it comes to rest on the shoulder 12. Whereafter, the screw is inserted into the portion 22 of the slot 19, and operates in the manner described above to flex the ear 21 into engagement with the casing.

In FIG. 4 which illustrates a modification of the base plate shown in FIG. 3 parts of the base plate common to the base plate shown in FIG. 3 are indicated by the same reference numeral. The plate 15a differs from the plate 15 in that over a l are between the points XX in FIG. 4, the periphery of the plate is relieved, with the exception of that portion of the periphery defining the chamfered portion .17. The radius of the chamfered portion 17 is then arranged to be equal to the radius of the plate 15a adjacent the chamfered portion 18, but

less than the radius of the chamfered portion 18. To

mount the base plate 15a in the distributor casing, the ear 21 is preferably initially bent inwards in a direction to close the slot 19. The plate can then be dropped into the casing without having to be tilted and will come to rest on the shoulder 12. Thereafter, the screw is inserted into the portion 22 of the slot 19 whereby the ear 21 is flexed outwardly so that the radius of the chamfered portion 17 becomes greater than the radius of the plate 15a and the portions 17, 18 engage in the groove in the casing to clamp the plate in position.

FIG. illustrates the assembled distributor, in which the loose plate is mounted in the casing 11 and the self-tapping screw is engaged in the slot 19 so as to urge the resilient ear 21 into clamping engagement with the groove 13. The cam shaft of the distributor, indicated at 31, then extends through the centrally disposed hole in the plate 15, which in turn supports the contact breaker assembly includes an angularly movable timing plate 32 which is coupled in conventional manner to the operating rod of a vacuum advance unit 33 and which carries the electrical contacts 34 of the contact breaker assembly. The arrangement of the contact breaker assembly is entirely conventional so that, in use, during rotation of the cam shaft 31 the contacts are alternately opened and closed so as to provide sparks at the sparking plugs of the engine utilizing the distributor in turn.

It is to be appreciated that the base plate described in the above examples could be provided with more than one chamfered region 18 (FIG. 7), in which case preferably the regions 18 and the ear 21 would be spaced around the periphery of the base plate, with the regions 18 all on the same side of a diameter of the plate, opposite the ear 21. Moreover, it is to be further appreciated that more than one ear 21 could be provided (FIG. 6),- and in the event that two ears 21 were provided they would desirably be diametrically opposite one another.

It is envisaged that the tapered screw which flexes the ear to a clamping position could be replaced by a simple wedge inserted into the slot 19 or by a POP rivet which is expanded in the portion 22 of the slot 19.

I claim:

1. An ignition distributor comprising a hollow substantially cylindrical casing formed internally with a support surface and a groove extending radially into the casing from the support surface, a contact breaker assembly base plate engaged with said support surface, said base plate being formed with a slot extending from the periphery thereof along a chord of the base plate to define a resilient ear integral with said base plate, and clamping means positioned between the resilient ear and the remainder of the base plate urging said resilient ear in a direction away from the remainder of the base plate so as to urge said resilient car into said groove and thereby clamp the base plate in position on the casing.

2. A distributor as claimed in claim 1 wherein said base plate is provided with a pair of peripherally extending chamfered portions formed respectively on the part of the base plate defining said resilient ear and a portion of the base plate diametrically opposite said resilient ear, said groove extending peripherally around the casing and being formed complementarily with said chamfered portions so that said clamping means urges said chamfered portions into engagement with said groove so as to c amp the base plate against axial and lateral movement relative to the casing.

3. A distributor as claimed in claim 2 wherein one of said chamfered portions projects from the periphery of the base plate.

4. A distributor as claimed in claim 3 wherein the regions of the periphery of the base plate on either side of the other of said chamfered portions are relieved so that said other chamfered portion projects beyond said relieved regions, said other chamfered portion having a radius equal to that of the periphery of the base plate adjacent said one chamfered portion and less than the radius of said one chamfered portion.

5. A distributor as claimed in claim 1 wherein the base plate is formed with a second resilient ear similar to and generally diametrically opposite the fist resilient ear, the distributor further including second clamping means associated with said second resilient ear, for urging said second resilient ear away from the remainder of the base plate into said groove.

6. A distributor as claimed in claim 1 wherein said base plate is provided with a first peripherally extending chamfered portion formed on the part of the base plate defining said resilient ear, 'and a plurality of further peripherally extending chamfered portions formed on portion of the base plate diametrically opposite said resilient ear, said further chamfered portions being all on one side of a diameter of the base plate.

7. A distributor as claimed in claim 1 wherein said clamping means comprises a tapered screw extending through said slot and engaged therein.

8. A distributor as claimed in claim 7 wherein said slot is provided with a part-circular portion intermediate the ends of the slot and said tapered screw is engaged in said part-circular portion.

9. A distributor as claimed in claim 1 wherein said clamping means includes a wedge engaged in said slot.

10. A distributor as claimed in claim 1 wherein said clamping means includes a POP rivet engaged in said slot. 

1. An ignition distributor comprising a hollow substantially cylindrical casing formed internally with a support surface and a groove extending radially into the casing from the support surface, a contact breaker assembly base plate engaged with said support surface, said base plate being formed with a slot extending from the periphery thereof along a chord of the base plate to define a resilient ear integral with said base plate, and clamping means positioned between the resilient ear and the remainder of the base plate urging said resilient ear in a direction away from the remainder of the base plate so as to urge said resilient ear into said groove and thereby clamp the base plate in position on the casing.
 2. A distributor as claimed in claim 1 wherein said base plate is provided with a pair of peripherally extending chamfered portions formed respectively on the part of the base plate defining said resilient ear and a portion of the base plate diametrically opposite said resilient ear, said groove extending peripherally around the casing and being formed complementarily with said chamfered portions so that said clamping means urges said chamfered portions into engagement with said groove so as to clamp the base plate against axial and lateral movement relative to the casing.
 3. A distributor as claimed in claim 2 wherein one of said chamfered portions projects from the periphery of the base plate.
 4. A distributor as claimed in claim 3 wherein the regions of the periphery of the base plate on either side of the other of said chamfered portions are relieved so that said other chamfered portion projects beyond said relieved regions, said other chamfered portion having a radius equal to that of the periphery of the base plate adjacent said one chamfered portion and less than the radius of said one chamfered portion.
 5. A distributor as claimed in claim 1 wherein the base plate is formed with a second resilient ear similar to and generally diametrically opposite the fist resilient ear, the distributor further including second clamping means associated with said second resilient ear, for urging said second resilient ear away from the remainder of the base plate into said groove.
 6. A distributor as claimed in claim 1 wherein said base plate is provided with a first peripherally extending chamfered portion formed on the part of the base plate defining said resilient ear, and a plurality of further peripherally extending chamfered portions formed on portion of the base plate diametrically opposite said resilient ear, said further chamfered portions being all on one side of a diameter of the base plate.
 7. A distributor as claimed in claim 1 wherein said clamping means comprises a tapered screw extending through said slot and engaged therein.
 8. A distributor as claimed in claim 7 wherein said slot is provided with a part-circular portion intermediate the ends of the slot and said tapered screw is engaged in said part-circular portion.
 9. A distributor as claimed in claim 1 wherein said clamping means includes a wedge engaged in said slot.
 10. A distributor as claimed in claim 1 wherein said clamping means includes a POP rivet engaged in said slot. 